1. Field of the Invention
This invention relates to a method for selective plating or etching on workpieces such as metals, semiconductors, insulators, etc. More particularly, the present invention relates to a selective plating or etching method which is best suited for the formation or correction of micro-patterns.
2. Description of the Prior Art
A selective plating method is known in which the workpiece is placed in an electroless plating solution and irradiated with energy beams to promote plating so that the irradiated portion alone is plated. Such method is for instance disclosed in U.S. Pat. No. 4,239,789. This prior art is described below.
U.S. Pat. No. 4,239,789 shows an example of nickel plating in which the workpiece having a nickel film deposited on the surface of a glass substrate is immersed in an electroless plating solution and energy beams are applied thereto to effect nickel plating on the nickel film.
In this example, energy beams, typically laser beams, emitted from an energy source are condensed through a lens system and then applied to the surface of the workpiece in the electroless plating solution. It is disclosed that nickel plating proceeds faster on the portion of the workpiece irradiated with laser beams than on other non-irradiated portion.
In this method, however, the workpiece must be immersed in its entirety in the plating solution to perform partial plating, so that when the workpiece is large, large equipment, especially a large-capacity plating cell, is required. Also, in correction or repair of a micro-pattern by plating according to this method, the portion where no correction is needed is also immersed in the plating solution, so that there is a possibility that such portion too, might be plated or corroded in the plating solution thereby reducing the quality of the product.